Circuit interrupter



Oct. 16, 1928.

F. ROBERSON CIRCUIT INTERRUPTER Filed April 9, 1926 2 Sheets-Sheet 1 rwemtor:V Frank FRODQPSOH,

b9 Mf/M I'TLS Attorney.

Oct. 16, 1928.

F. ROBERSON CIRCUIT INTERRUPTER Filed April 9, 1926 2 Sheets-Sheet 2 .Fuga

Inventor: Frank Robebom HL@Attorney,Y

Patented Qct. 16, 1928.

UNITED, STATES ,PATENT OFFICE,

FRANK ROBERSON, or GARY, INDIANA,V AssIeNon To GENERAL nLEC'rRiC COMPANY, A CORPORATION OF NEW YORK.

CIRCUIT INTERRUPTER. Y i

Appimatimfiiea April 9,

My invention relates to improvements yin dependently movable switch members in circircuit interrupters, particularly automatic Overloadcircuit interrupters ot the high speed flux shifting type that ordinarily respond only to excessive currents iiowing in a predetermined diiectioii. The improvements provided by the present invention enable a circuit interrupter of the above type to protect alternating current-circuits, as welll as direct current Circuits in'which current may flow in either direction.

More specificallythepresent invention is any improvement upon the type of high speed flux shifting Circuit` interruptor described and claimed in my Patent No. 1,566,122 of December 15, 1925. In my patented type of circuit interruptor a pair Oi cooperat ing movable circuit controlling ymembers are operable into circuitV closing engagement and each is stronglydbiased to the circuit interrupting position. An electronen et is provided with separate poles for e ectromagnetically holding each switch member `in the circuit closing position. The release of each switch member is controlled by a common magnet-ized winding or current conductor which is arrangedto shift the liux fot the holding electromagnet so as to instantly decrease the magnetic holding eect of all thepoles of theholding electromagnet when a current of excessive valuelows in a predetermined direction through the rcleasing winding or conductor.

1n accordance with my present invention the iux shifting winding or conductor is arranged to eiiect the release of one o r the other ot' the pair or' cooperating circuit controlling members depending upon the direction in which the excessive current flows through the releasing winding orcon'ductor. In this way a high speed circuit interruptor of tlietype described in my above noted Vpatent isy rendered capable oi' affording protection to alternating current circuits or to direct currentcircuits in which the current' lmay flow 'in either direction since atleast- One et' the circuit controlling members is always released to move out of engagement with tlieco-operating member kupon a predetermined curreiit flow in'y either direction in the circuit controlled the interrupter.

- Briefly,`in carrying the present invention ent, the switch members 10and 1l are held into effect in a circuit interrupter having a holding electromagnet with separate pairs of poles for maintaining the cooperating ini926; semi No. 100,976.

`iiowing through the releasing conductor or winding the action upon one pair of the poles of the holding electromagnet is such `as to release the switch member held. thereby, while hand, with current iiowing through the releasing condiictor or winding in the opposite or reverse direction, the relative action upon the several poles of the'holding'electromagnet is also reversed so that'the other switch inemberis released while theiirst switch member is held more lirmly in engagement with the cooperating pole of the holding-eleci* 'tromagnet Thus .irrespective ofV the directionl in whichcurrent is supplied to the releasing conductor or winding one V,o the switch members Valways is released when the currentliowing in either direction eXceedsf a predeterminedv value.

Figs. 1 and 2 of the accompanying drawing diagrammatically illustrate an embodiment of the present invention-in aV high speed electromagnetic circuit interrupter of the f `type disclosed in my prior Patent f No.

1,566,122 of December 15, 1925. Figs. v3` andV 4 showdiagrammaticallya modification of the arrangement illustrated'in Figs. land 2.

Referring to Fifi., 1, the circuit interrupter embodyingmy inventionis'ot the general 'form described andl claimed in my prior patent previously mentioned, and consists cssentially .of two cooperating Aindependently movable switch members 10 and 11 which `are' each strongly biased tothe circuit interrupting position by means of the biasing springs -12 and 13 respectively and are Apiv fotally `mounted to rotate about the pivots `14: and 15. ,The movable switch members are provided with suitable yielding contacts 16 and Y17 which are arranged ,to move vc5 the action upon the other'pair of poles isy ysuch as to more firmly hold the switch membercOOperating therewith. On the other into circuit closing engagement vwhen the Y switch arms 10and 11 are operated totheir respective circuit closingpositions.

As more fully set vforth in my priorA par in the circuit closing position by the magnetic attraction of the magnetic members 18 iiol and 19, which are carried respectively by 'the switch members 10 and 11 with the cooperat= ing poles ,2O and 21 of the holding electromagnet 22.` The magnetiing winding 284 of the holding electromagn'et sets up a flux in the magnetic structure thereof in such direction that the poles 2() and 21 are of corresponding polarity as indicatedby the notations N and S in the drawing. The magnetic attraction between the magnetic members 18 and 19 andthe cooperating poles 20 and 21 servesto hold the switch members 10 Iand 11 in the circuit closing position when operated thereto through the agency or suitable closing mechanism such asthe combined manual and electromagnetic closing devices 24 and 25 illustrated in the drawing.

The release of the magnetic members 18 and 19; and consequently or the corresponding switch members 10 and 11, iscontrolled by the releasing conductor or Winding 26 which isv connected in the circuit controller by the interrupter extending from the terminal 27 through a suitable flexiblefconnector to lthe contact 17, thence through the cooperating contact v16 and a similar iexible connector connecting the latter to the releasing conductor 26. The releasing conductor 26 is oiiset or looped as more iully shown in Fig. 2 to form a Z or S shaped bucking bar in cooperating magnetic relation with the pairs or poles'20 and 21 of the holding electromagnet 20 and is connected to the other terminal 28 of the circuit interrupter.

As shown more clearly in Fig. 2, the magnetic relation of the offset portion of bucking bar 26 with the poles 20 and 21 is such that the portion 26'DL of the bucking bar serves to shift the holding flux from the magnetic member 18 and thereby release the switch member 10 when a current oit predetermined value iiows through the bucking bar in the direction indicated by the arrows, While the portion 26b serves to increase the holding eiect upon the magnetic member 19 and thereby more firmly hold the switch member 11 in the circuit closing position. Conversely with the current flowing through the bucking bar in the opposite or reverse direct-ion from that indicated by the arrows the portion 26b serves to shift the holding flux from the magnetic member 19 to release the switch Vmember 11 and the portion 26 functions to more Iirmly maintain the magnetic member 18 in attracted engagement with the poles 20. The manner in which each portion of the bucking bar functions to shift the flux from the magnetic members 18 and 19 is fully described and claimed in the Tritle reissue Patent No. 15,441,1or August 29, 1922.

From the foregoing the operation of the circuit inter'rupter shown in Fig. 1 to ai'ord overload protection to either an alternating current or a direct current will be clear. When the alternating current or the direct current is increased to an abnormal value .by the occurrence of short circuit or excessive overload, one or the other of the switch members 10 or 11, dependent upon the direction in which current ilows through the bucking bar 26 at the instant o'l` excessive current value, is released to permit the correspon ding biasing spring 12 or 13 to quickly operate the respective switch member to the circuit interrupting position. This permits the 1nterrupter to safely and successfully break the circuit in response to an excessive current flow in either' direction in the circuit controlled by the interrupter. l y

In the modilied arrangement shown in Figs. and Ll the magnetic structure of the holding electromagnet is rearranged so that the holding flux tor the poles 2O is supplied by the magnetizing winding 27, Whi e the holding flug; io'r the poles 21 is supplied by the n'lagnetizing 'winding' 28. Furthermore, the relative direction in which magnetizing linx is supplied to the poles 20 and 21 so that the poles havev opposite polarities is indicated by the notations N, S, and N S', in Fig. 3. Vith the polarity of the poles reversed the releasing conductor or bucking bar 26 is formed in a simple U shape and may be energized from the secondary of a current transformer 29 connected in the circuit controlled by the interrupter contacts 16 and 17. The U shaped bucking bar 26 serves to shift the flux in one or the other pair of poles 2O and 21 to release the cooperating magnetic members 18 and 19 in substantially the same manner as previously described. In this case, the predetermined flow of current through the portion 26c or the releasing Winding or bucking bar 26 in the direction indicated by arrows in Fig. 4 serves to shirt the flux in the )air or poles 2O to release the magnetic memlber 18, while thetlow or current through the portion 26d o'l the bucking bar serves to increase the magnetic traction upon the member 19. iVith aiow of current through the releasing winding or bucking bar7 26 in the reverse direction, the portion 26d then shifts the holding flux from the magnetic member 19 and the portion 26c increases the holding effect upon the magnetic member 18. As the holding flux is supplied to the poles 20 and 21 in the arrangement shown in Fig. 3 through separatemagnetic flux paths, the possibility or' interference between the opposite magnetic actions of the sections 26C and 26(1 of the bucking bar is effectively prevented.

While have described a preferred embodiment of my invention, it should be understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

That I claim as new and desire. to secure by Letters Patent of the United States is 1, A high speed circuit interrupter for an electric circuit adapted to carry current in either direction comprising a vpair ot' cooperating independently movable switch members operable together into circuit closing engagement and biased apart to interrupt the circuit jointly controlled tliereby,electrom`ag netic means providing separate flux paths for holding each of said members inthe circuit closing'position, and means for providing additional flux paths for the holding flux of said electromagnetic means to release one o't' said switch members for *operation to interrupt the circuit jointlyv controlled thereby in accordance Iwith its bias upon a predetermined Current flow in one direction in the circuit controlled by the interrupter and to release the other of said switch members for operation to interrupt the circ-uit jointly controlled thereby in accordance with its bias upon a predetermined current flow in the reverse din rection in the circuit controlled by the interi'upter.

2. A high speed circuit interrupter for an electric circuit adapted yto carry current in either direction comprising a pair o cooperating independently movable switch menibers operable together into circuit closing engageinentand biased apart to interrupt the circuit jointly Controlled thereby, electromagnetic means having a plurality of pairs of poles disposed between the switch members i for separately holding said members in the circuit closing position, and means energized,

in accordance with the current in the circuit controlled-by` the interrupter and cooperating with said poles to release a corresponding one of said switch members for operation to in` Yterrupt the circuit jointly controlled thereby yin accordance with its bias upon a predetermined current i'low in eachdirection in the controlled circuit.

3. A high speed circuit interrupter for an electric circuit adapted to carry current in either direction comprising a pair of cooperating independently movable switch members operable together into circuit closing engagement and biased apart to interrupt the circuit joint-ly controlled thereby, electromag-` netic means having a separate flux path tor magnetically holding each oi said switch members in the circuit closing position, and means responsive to the current in the circuit controlled by the interrupter for providing an additional path for the holding i'lux in a corresponding one ot said flux paths upon a predetermined current flow in each direction inthe controlled circuit and thereby permit the corresponding one of said switch members to operate out of engagement with the cooperating switch member to interrupt the circuit jointly controlled thereby in accordance with its bias.

4. A high speed circuit interrupter for an electric circuit adaptedto carry current in either direction comprising a pair of cooperating 'i ,independently l movable i switch members operable togetherinto circuit closing engagement andbiased apart to interrupt ing path for the holding iluirthereoi"v independently oit a predetermined oneo said magnetic members to effect the release of the corresponding one of said switch members upon a predetermined current flow in each direction in the controlled circuit. p

5. A high speed circuit interrupter for an electric circuit adapted to carry current in either direction comprising a pair of cooperating independently movable switch members operable together into circuit closing engagement and biased apart to interrupt the circuit jointly controlled thereby, electromagnetic means including a pair ot' movable magnetic members operable into a predetermined spaced relationand each connected to a corresponding one of said switch members for separately holding said switch members in the circuit closing position, and windings interposed between said niagentic members and energized in accordance with the current in the circuit controlled by the interrupter to shift the magnetic holding flux from a corresponding one of said magnetic members upon a predetermined current flow in either direction in the circuit controlled by the interrupter to permit the corresponding switch member to operate out of engagement with the cooperating switch member in accorda-nce circuit jointly with its bias to interrupt the controlled thereby. Y

' 6. A high speed circuit interrupter for an electric circuit adapted to carry current in either direction comprising a pair of cooperating independently movable switch members operable together into circuit closing engagement and biased apart to interrupt the circuit jointly Vcontrolled thereby, electromagnetic means having separate pairs of poles interposed between. said members for electromagnetically holding said switch members together in the circuit closing position, and

means energized in accordance with the cui'- rent in the circuit controlled by the interrupter for oppositelyvarying the holding effect of said pairs of poles to effect the release of only one of said switch members for operation to interrupt the circuit jointly controlled Y thereby in accordance with its bias upon a predetermined current `flow in each direction in the circuit controlled by the interrupter.

7. A high speed circuit interrupter for an electric circuit adapted to carry current in either direction comprising a pair of cooperating independently movable switch members operable together into circuit closing engage.-

y ment and biased apart to interrupt the circuit jointly controlled thereby, electromagnetic means including a pair of movable magnetic memberseach mounted .upon a` corresponding one of said switch, members and electromagneticfmeans having-separate pairs of poles disposed in spaced relation between the said switch members and cooperating with each magnetic member to hold the corresponding switch member in the circuit closing position when operated thereto, `and windings energized in accordance with the current in the circuit controlled by the intcrrupter and intei-posed between each of said pairs out' poles for shifting the holding 'flux from a corresponding one of said magnetic members upon a predetermined current flow in each direction in the circuit controlled by the interrupter to permit a corresponding switch member to operate out of engagement with the cooperating switch member to interrupt the circuit jointly controlled thereby in accordancel with its bias.

In witness whereof, I have hereunto set my hand this second day of April, 1926.

FRANK RoBERsoN. 

